#ifndef _ITERATOR_H
#define _ITERATOR_H

// author: Owen Astrachan
// for cps 100, 8/23/95
// modified for abstract base class 11/8/95


template <class Kind>
class Iterator
{
  public:
    virtual ~Iterator() {};    
    virtual void First() = 0;                 // must call for first element
    virtual bool IsDone() const = 0;          // true -> no more elements
    virtual void Next() = 0;                  // advance to next element
    virtual const Kind & Current() const = 0; // return current element
    virtual Kind & Current() = 0;             // return modifiable current
};

#endif